There is evidence that exposure to certain Superfund chemicals (e.g., PCBs) can be implicated in the development of cardiovascular diseases such as atherosclerosis. Studies also suggest that high-fat diets are associated with a high risk of heart and blood vessel diseases. Because of similar lipolytic properties, the cytotoxicity of PCBs may be influenced by the type of dietary dat that is being consumed. Our preliminary evidence suggests that oxidative stress is a critical event in PCB-mediated endothelial cell dysfunction. Because of its constant exposure to blood components, including environmental contaminants, pro-oxidants, stress and dysfunction. Thus, it is very likely that certain diet-derived fats, especially unsaturated fats, can greatly alter the cellular lipid and oxidant/antioxidant environment and thus further compromise the PCB- mediated endothelial integrity. A major focus of the present proposal will be to test the hypothesis that specific dietary fats can potentiate PCB- mediated endothelial cell dysfunction and that specific nutrient interventions, such as increasing the intake of antioxidant nutrients/chemicals (e.g., vitamin E and glutathione precursors), can provide protection against PCB/lipid-mediated atherosclerosis. To test this hypothesis, we will study he commercially available saturated and polyunsaturated fat sources. Because diet-derived lipids are carried and packaged in the blood as lipoproteins, it also will be necessary to feed animals (rabbits) diet enriched with the above mentioned fats and study the effects of lipoproteins derived from these animals on PCB- compromised endothelial cell integrity. Finally, an ApoE knock-out mouse model, which mimics the pathology of human atherosclerosis, will be utilized to correlate the effects of dietary dat and PCBs on atherogenic markers of endothelial cell dysfunction. Results from this work will provide valuable information towards therapeutic nutrition intervention for populations at or near Superfund sites.